1. Technical Field
The present invention relates to a method and an apparatus for automatically supplying a pattern signal for testing a video display device and, more particularly to a method and an apparatus for automatically supplying a pattern signal necessary for testing and adjusting a screen of a video display device such as a cathode ray tube (CRT) assembly in a product manufacturing line.
2. Related Art
Generally, a video display device such as a cathode ray tube (CRT) as manufactured, for example, in U.S. Pat. No. 4,790,785 for Means And Method For Manufacture For A High Resolution Color Cathode Ray Tube issued to Lee et al., U.S. Pat. No. 4,950,192 for Method Of Manufacturing Of Color Display Tube issued to Rietdijk et al., and U.S. Pat. No. 4,925,421 for Method For Manufacturing A Color Cathode Ray Tube And A Color Cathode Ray Tube issued to van den Broek, must be tested and adjusted to correct display deviations and distortions in a production assembly line.
Conventionally, the test and adjustment of display deviations and distortions of a CRT assembly mainly rely upon physical labor. The CRT assembly must pass though a series of essential tests and adjustments in a production assembly line. Exemplars of testing techniques of CRT assembly in a production assembly line are disclosed in U.S. Pat. No. 4,757,239 for CRT Display System With Automatic Alignment Employing Personality Memory issued to Starkey, IV, U.S. Pat. No. 5,216,504 for Automatic Precision Video Monitor Alignment System issued to Webb et al., U.S. Pat. No. 5,442,391 for Method And A System For Testing A Cathode Ray Tube Or Like Products issued to Hung et al., U.S. Pat. No. 5,526,043 for Automatic Video Display Testing And Adjusting System issued to Wen, and U.S. Pat. No. 5,638,461 for Stereoscopic Electro-Optical System For Automated Inspection And/Or Alignment Of Image Devices On A Production Assembly Line issued to Fridge.
During a process of adjusting a screen of the CRT assembly, a human operator supplies a variety of test signals from a measurement instrument to the CRT assembly through a signal cable and a microprocessor cable for testing and adjustment, i.e., a vertical synchronization signal, a horizontal synchronization signal and a direct digital control (DDC) signal. After the screen of the CRT assembly is tested and adjusted, the operator must physically separate the signal cable and the microprocessor cable and transport the signal cable and the microprocessor cable to a next operating line. Since the operator must manually connect and separate the microprocessor cable and the signal cable of the CRT assembly to/from the measurement instrument, I have observed that the screen testing and adjustment can be extremely cumbersome and inconvenient. Moreover, as the working hours are increased for the operator at the production assembly line, the test time is increased and the production quality is lowered.